This invention is related in general to microelectromechanical systems (MEMS) and, more specifically, to optical switch implementations using frequency-based addressing and/or control of MEMS components.
Micromechanical structures incorporated into MEMS have advantages over larger designs that accomplish the same or similar functionality because of their smaller size, potentially lower cost of manufacturing, lower power requirements, and better, sometimes unique performance characteristics. A sampling of micromechanical devices that have been built using MEMS-fabrication techniques includes accelerometers, gyroscopes, temperature sensors, chemical sensors, AFM (atomic force microscope) probes, micro-lenses, shutter-actuators, etc. Such devices can be integrated with microelectronics, packaging, optics, and/or other devices or components to realize complete systems. Some examples of MEMS include units that perform inertial measurement, head-mounted displays, wireless gyro-mice, and large display systems.
Some MEMS applications employ arrays of components, such as micromirrors used in digital mirror displays. In array-based MEMS applications, a component design is repeated multiple times (e.g., in one or more rows or columns) to populate an area of the microsystem (e.g., a silicon chip). Typically, each of these distributed components is sensed or controlled individually so that a selected component or selected subset of the total number of components can be used or “addressed” at one time.
One problem with addressing components in a MEMS array using electronic selection is the number of interconnections, multiplexing provisions, and control or other structures that may be needed for successful operation. Building this selection capability into array-based MEMS increases their size, failure susceptibility, complexity of design and manufacture, and cost.
Another problem is that the electronic needs for the selection process are best met with relatively sophisticated integrated circuit (IC) processing, while any mechanical elements in the process often demand equally sophisticated mechanical-device processing. Successfully carrying both processes through on an array (i.e., “mixed-mode processing”) is a difficult design challenge. Further, switch implementations using MEMS devices have been found to be particularly susceptible to the problems enumerated above.